Host/Target specific installation notes for GCC

Note that this list of install notes is not a list of supported
hosts or targets. Not all supported hosts and targets are listed
here, only the ones that require host-specific or target-specific
information are.

alpha*-*-*

This section contains general configuration information for all
alpha-based platforms using ELF (in particular, ignore this section for
DEC OSF/1, Digital UNIX and Tru64 UNIX). In addition to reading this
section, please read all other sections that match your target.

We require binutils 2.11.2 or newer.
Previous binutils releases had a number of problems with DWARF 2
debugging information, not the least of which is incorrect linking of
shared libraries.

Support for Tru64 UNIX V5.1 has been obsoleted in GCC 4.7, but can still
be enabled by configuring with --enable-obsolete. Support will
be removed in GCC 4.8. As of GCC 4.6, support for Tru64 UNIX V4.0 and
V5.0 has been removed. As of GCC 3.2, versions before
alpha*-dec-osf4 are no longer supported. (These are the versions
which identify themselves as DEC OSF/1.)

On Tru64 UNIX, virtual memory exhausted bootstrap failures
may be fixed by reconfiguring Kernel Virtual Memory and Swap parameters
per the /usr/sbin/sys_check Tuning Suggestions,
or applying the patch in
http://gcc.gnu.org/ml/gcc/2002-08/msg00822.html. Depending on
the OS version used, you need a data segment size between 512 MB and
1 GB, so simply use ulimit -Sd unlimited.

As of GNU binutils 2.22, neither GNU as nor GNU ld
are supported on Tru64 UNIX, so you must not configure GCC with
--with-gnu-as or --with-gnu-ld.

Cross-compilers for the Tru64 UNIX target currently do not work because
the auxiliary programs mips-tdump and mips-tfile can't
be compiled on anything but Tru64 UNIX.

GCC writes a ‘.verstamp’ directive to the assembler output file
unless it is built as a cross-compiler. It gets the version to use from
the system header file /usr/include/stamp.h. If you install a
new version of Tru64 UNIX, you should rebuild GCC to pick up the new version
stamp.

GCC now supports both the native (ECOFF) debugging format used by DBX
and GDB and an encapsulated STABS format for use only with GDB. See the
discussion of the --with-stabs option of configure above
for more information on these formats and how to select them.

There is a bug in DEC's assembler that produces incorrect line numbers
for ECOFF format when the ‘.align’ directive is used. To work
around this problem, GCC will not emit such alignment directives
while writing ECOFF format debugging information even if optimization is
being performed. Unfortunately, this has the very undesirable
side-effect that code addresses when -O is specified are
different depending on whether or not -g is also specified.

To avoid this behavior, specify -gstabs+ and use GDB instead of
DBX. DEC is now aware of this problem with the assembler and hopes to
provide a fix shortly.

DOS

You cannot install GCC by itself on MSDOS; it will not compile under
any MSDOS compiler except itself. You need to get the complete
compilation package DJGPP, which includes binaries as well as sources,
and includes all the necessary compilation tools and libraries.

epiphany-*-elf

Adapteva Epiphany.
This configuration is intended for embedded systems.

*-*-freebsd*

Support for FreeBSD 1 was discontinued in GCC 3.2. Support for
FreeBSD 2 (and any mutant a.out variants of FreeBSD 3) was
discontinued in GCC 4.0.

In order to better utilize FreeBSD base system functionality and match
the configuration of the system compiler, GCC 4.5 and above as well as
GCC 4.4 past 2010-06-20 leverage SSP support in libc (which is present
on FreeBSD 7 or later) and the use of __cxa_atexit by default
(on FreeBSD 6 or later). The use of dl_iterate_phdr inside
libgcc_s.so.1 and boehm-gc (on FreeBSD 7 or later) is enabled
by GCC 4.5 and above.

We support FreeBSD using the ELF file format with DWARF 2 debugging
for all CPU architectures. You may use -gstabs instead of
-g, if you really want the old debugging format. There are
no known issues with mixing object files and libraries with different
debugging formats. Otherwise, this release of GCC should now match
more of the configuration used in the stock FreeBSD configuration of
GCC. In particular, --enable-threads is now configured by
default. However, as a general user, do not attempt to replace the
system compiler with this release. Known to bootstrap and check with
good results on FreeBSD 7.2-STABLE. In the past, known to bootstrap
and check with good results on FreeBSD 3.0, 3.4, 4.0, 4.2, 4.3, 4.4,
4.5, 4.8, 4.9 and 5-CURRENT.

The version of binutils installed in /usr/bin probably works
with this release of GCC. Bootstrapping against the latest GNU
binutils and/or the version found in /usr/ports/devel/binutils has
been known to enable additional features and improve overall testsuite
results. However, it is currently known that boehm-gc (which itself
is required for java) may not configure properly on FreeBSD prior to
the FreeBSD 7.0 release with GNU binutils after 2.16.1.

h8300-hms

The calling convention and structure layout has changed in release 2.6.
All code must be recompiled. The calling convention now passes the
first three arguments in function calls in registers. Structures are no
longer a multiple of 2 bytes.

hppa*-hp-hpux*

Support for HP-UX version 9 and older was discontinued in GCC 3.4.

We require using gas/binutils on all hppa platforms. Version 2.19 or
later is recommended.

It may be helpful to configure GCC with the
--with-gnu-as and
--with-as=... options to ensure that GCC can find GAS.

The HP assembler should not be used with GCC. It is rarely tested and may
not work. It shouldn't be used with any languages other than C due to its
many limitations.

Specifically, -g does not work (HP-UX uses a peculiar debugging
format which GCC does not know about). It also inserts timestamps
into each object file it creates, causing the 3-stage comparison test to
fail during a bootstrap. You should be able to continue by saying
‘make all-host all-target’ after getting the failure from ‘make’.

Various GCC features are not supported. For example, it does not support weak
symbols or alias definitions. As a result, explicit template instantiations
are required when using C++. This makes it difficult if not impossible to
build many C++ applications.

There are two default scheduling models for instructions. These are
PROCESSOR_7100LC and PROCESSOR_8000. They are selected from the pa-risc
architecture specified for the target machine when configuring.
PROCESSOR_8000 is the default. PROCESSOR_7100LC is selected when
the target is a ‘hppa1*’ machine.

The PROCESSOR_8000 model is not well suited to older processors. Thus,
it is important to completely specify the machine architecture when
configuring if you want a model other than PROCESSOR_8000. The macro
TARGET_SCHED_DEFAULT can be defined in BOOT_CFLAGS if a different
default scheduling model is desired.

As of GCC 4.0, GCC uses the UNIX 95 namespace for HP-UX 10.10
through 11.00, and the UNIX 98 namespace for HP-UX 11.11 and later.
This namespace change might cause problems when bootstrapping with
an earlier version of GCC or the HP compiler as essentially the same
namespace is required for an entire build. This problem can be avoided
in a number of ways. With HP cc, UNIX_STD can be set to ‘95’
or ‘98’. Another way is to add an appropriate set of predefines
to CC. The description for the munix= option contains
a list of the predefines used with each standard.

More specific information to ‘hppa*-hp-hpux*’ targets follows.

hppa*-hp-hpux10

For hpux10.20, we highly recommend you pick up the latest sed patch
PHCO_19798 from HP.

The C++ ABI has changed incompatibly in GCC 4.0. COMDAT subspaces are
used for one-only code and data. This resolves many of the previous
problems in using C++ on this target. However, the ABI is not compatible
with the one implemented under HP-UX 11 using secondary definitions.

hppa*-hp-hpux11

GCC 3.0 and up support HP-UX 11. GCC 2.95.x is not supported and cannot
be used to compile GCC 3.0 and up.

The libffi and libjava libraries haven't been ported to 64-bit HP-UX and don't build.

Refer to binaries for information about obtaining
precompiled GCC binaries for HP-UX. Precompiled binaries must be obtained
to build the Ada language as it can't be bootstrapped using C. Ada is
only available for the 32-bit PA-RISC runtime.

Starting with GCC 3.4 an ISO C compiler is required to bootstrap. The
bundled compiler supports only traditional C; you will need either HP's
unbundled compiler, or a binary distribution of GCC.

It is possible to build GCC 3.3 starting with the bundled HP compiler,
but the process requires several steps. GCC 3.3 can then be used to
build later versions. The fastjar program contains ISO C code and
can't be built with the HP bundled compiler. This problem can be
avoided by not building the Java language. For example, use the
--enable-languages="c,c++,f77,objc" option in your configure
command.

There are several possible approaches to building the distribution.
Binutils can be built first using the HP tools. Then, the GCC
distribution can be built. The second approach is to build GCC
first using the HP tools, then build binutils, then rebuild GCC.
There have been problems with various binary distributions, so it
is best not to start from a binary distribution.

On 64-bit capable systems, there are two distinct targets. Different
installation prefixes must be used if both are to be installed on
the same system. The ‘hppa[1-2]*-hp-hpux11*’ target generates code
for the 32-bit PA-RISC runtime architecture and uses the HP linker.
The ‘hppa64-hp-hpux11*’ target generates 64-bit code for the
PA-RISC 2.0 architecture.

The script config.guess now selects the target type based on the compiler
detected during configuration. You must define PATH or CC so
that configure finds an appropriate compiler for the initial bootstrap.
When CC is used, the definition should contain the options that are
needed whenever CC is used.

Specifically, options that determine the runtime architecture must be
in CC to correctly select the target for the build. It is also
convenient to place many other compiler options in CC. For example,
CC="cc -Ac +DA2.0W -Wp,-H16376 -D_CLASSIC_TYPES -D_HPUX_SOURCE"
can be used to bootstrap the GCC 3.3 branch with the HP compiler in
64-bit K&R/bundled mode. The +DA2.0W option will result in
the automatic selection of the ‘hppa64-hp-hpux11*’ target. The
macro definition table of cpp needs to be increased for a successful
build with the HP compiler. _CLASSIC_TYPES and _HPUX_SOURCE need to
be defined when building with the bundled compiler, or when using the
-Ac option. These defines aren't necessary with -Ae.

It is best to explicitly configure the ‘hppa64-hp-hpux11*’ target
with the --with-ld=... option. This overrides the standard
search for ld. The two linkers supported on this target require different
commands. The default linker is determined during configuration. As a
result, it's not possible to switch linkers in the middle of a GCC build.
This has been reported to sometimes occur in unified builds of binutils
and GCC.

A recent linker patch must be installed for the correct operation of
GCC 3.3 and later. PHSS_26559 and PHSS_24304 are the
oldest linker patches that are known to work. They are for HP-UX
11.00 and 11.11, respectively. PHSS_24303, the companion to
PHSS_24304, might be usable but it hasn't been tested. These
patches have been superseded. Consult the HP patch database to obtain
the currently recommended linker patch for your system.

The patches are necessary for the support of weak symbols on the
32-bit port, and for the running of initializers and finalizers. Weak
symbols are implemented using SOM secondary definition symbols. Prior
to HP-UX 11, there are bugs in the linker support for secondary symbols.
The patches correct a problem of linker core dumps creating shared
libraries containing secondary symbols, as well as various other
linking issues involving secondary symbols.

GCC 3.3 uses the ELF DT_INIT_ARRAY and DT_FINI_ARRAY capabilities to
run initializers and finalizers on the 64-bit port. The 32-bit port
uses the linker +init and +fini options for the same
purpose. The patches correct various problems with the +init/+fini
options, including program core dumps. Binutils 2.14 corrects a
problem on the 64-bit port resulting from HP's non-standard use of
the .init and .fini sections for array initializers and finalizers.

Although the HP and GNU linkers are both supported for the
‘hppa64-hp-hpux11*’ target, it is strongly recommended that the
HP linker be used for link editing on this target.

At this time, the GNU linker does not support the creation of long
branch stubs. As a result, it can't successfully link binaries
containing branch offsets larger than 8 megabytes. In addition,
there are problems linking shared libraries, linking executables
with -static, and with dwarf2 unwind and exception support.
It also doesn't provide stubs for internal calls to global functions
in shared libraries, so these calls can't be overloaded.

The HP dynamic loader does not support GNU symbol versioning, so symbol
versioning is not supported. It may be necessary to disable symbol
versioning with --disable-symvers when using GNU ld.

POSIX threads are the default. The optional DCE thread library is not
supported, so --enable-threads=dce does not work.

*-*-linux-gnu

Versions of libstdc++-v3 starting with 3.2.1 require bug fixes present
in glibc 2.2.5 and later. More information is available in the
libstdc++-v3 documentation.

i?86-*-linux*

As of GCC 3.3, binutils 2.13.1 or later is required for this platform.
See bug 10877 for more information.

If you receive Signal 11 errors when building on GNU/Linux, then it is
possible you have a hardware problem. Further information on this can be
found on www.bitwizard.nl.

i?86-*-solaris2.[89]

The Sun assembler in Solaris 8 and 9 has several bugs and limitations.
While GCC works around them, several features are missing, so it is
recommended to use the GNU assembler instead. There is no bundled
version, but the current version, from GNU binutils 2.22, is known to
work.

Solaris 2/x86 doesn't support the execution of SSE/SSE2 instructions
before Solaris 9 4/04, even if the CPU supports them. Programs will
receive SIGILL if they try. The fix is available both in
Solaris 9 Update 6 and kernel patch 112234-12 or newer. There is no
corresponding patch for Solaris 8. To avoid this problem,
-march defaults to ‘pentiumpro’ on Solaris 8 and 9. If
you have the patch installed, you can configure GCC with an appropriate
--with-arch option, but need GNU as for SSE2 support.

i?86-*-solaris2.10

Use this for Solaris 10 or later on x86 and x86-64 systems. Starting
with GCC 4.7, there is also a 64-bit ‘amd64-*-solaris2.1[0-9]*’ or
‘x86_64-*-solaris2.1[0-9]*’ configuration that corresponds to
‘sparcv9-sun-solaris2*’.

It is recommended that you configure GCC to use the GNU assembler, in
/usr/sfw/bin/gas. The versions included in Solaris 10, from GNU
binutils 2.15, and Solaris 11, from GNU binutils 2.19, work fine,
although the current version, from GNU binutils
2.22, is known to work, too. Recent versions of the Sun assembler in
/usr/ccs/bin/as work almost as well, though.

For linking, the Sun linker, is preferred. If you want to use the GNU
linker instead, which is available in /usr/sfw/bin/gld, note that
due to a packaging bug the version in Solaris 10, from GNU binutils
2.15, cannot be used, while the version in Solaris 11, from GNU binutils
2.19, works, as does the latest version, from GNU binutils 2.22.

To use GNU as, configure with the options
--with-gnu-as --with-as=/usr/sfw/bin/gas. It may be necessary
to configure with --without-gnu-ld --with-ld=/usr/ccs/bin/ld to
guarantee use of Sun ld.

ia64-*-linux

If you are using the installed system libunwind library with
--with-system-libunwind, then you must use libunwind 0.98 or
later.

None of the following versions of GCC has an ABI that is compatible
with any of the other versions in this list, with the exception that
Red Hat 2.96 and Trillian 000171 are compatible with each other:
3.1, 3.0.2, 3.0.1, 3.0, Red Hat 2.96, and Trillian 000717.
This primarily affects C++ programs and programs that create shared libraries.
GCC 3.1 or later is recommended for compiling linux, the kernel.
As of version 3.1 GCC is believed to be fully ABI compliant, and hence no
more major ABI changes are expected.

ia64-*-hpux*

Building GCC on this target requires the GNU Assembler. The bundled HP
assembler will not work. To prevent GCC from using the wrong assembler,
the option --with-gnu-as may be necessary.

The GCC libunwind library has not been ported to HPUX. This means that for
GCC versions 3.2.3 and earlier, --enable-libunwind-exceptions
is required to build GCC. For GCC 3.3 and later, this is the default.
For gcc 3.4.3 and later, --enable-libunwind-exceptions is
removed and the system libunwind library will always be used.

*-ibm-aix*

Support for AIX version 3 and older was discontinued in GCC 3.4.
Support for AIX version 4.2 and older was discontinued in GCC 4.5.

“out of memory” bootstrap failures may indicate a problem with
process resource limits (ulimit). Hard limits are configured in the
/etc/security/limits system configuration file.

GCC can bootstrap with recent versions of IBM XLC, but bootstrapping
with an earlier release of GCC is recommended. Bootstrapping with XLC
requires a larger data segment, which can be enabled through the
LDR_CNTRL environment variable, e.g.,

% LDR_CNTRL=MAXDATA=0x50000000
% export LDR_CNTRL

One can start with a pre-compiled version of GCC to build from
sources. One may delete GCC's “fixed” header files when starting
with a version of GCC built for an earlier release of AIX.

To speed up the configuration phases of bootstrapping and installing GCC,
one may use GNU Bash instead of AIX /bin/sh, e.g.,

% CONFIG_SHELL=/opt/freeware/bin/bash
% export CONFIG_SHELL

and then proceed as described in the build instructions, where we strongly recommend specifying an absolute path
to invoke srcdir/configure.

Because GCC on AIX is built as a 32-bit executable by default,
(although it can generate 64-bit programs) the GMP and MPFR libraries
required by gfortran must be 32-bit libraries. Building GMP and MPFR
as static archive libraries works better than shared libraries.

Errors involving alloca when building GCC generally are due
to an incorrect definition of CC in the Makefile or mixing files
compiled with the native C compiler and GCC. During the stage1 phase of
the build, the native AIX compiler must be invoked as cc
(not xlc). Once configure has been informed of
xlc, one needs to use ‘make distclean’ to remove the
configure cache files and ensure that CC environment variable
does not provide a definition that will confuse configure.
If this error occurs during stage2 or later, then the problem most likely
is the version of Make (see above).

The native as and ld are recommended for bootstrapping
on AIX. The GNU Assembler, GNU Linker, and GNU Binutils version 2.20
is required to bootstrap on AIX 5. The native AIX tools do
interoperate with GCC.

Building libstdc++.a requires a fix for an AIX Assembler bug
APAR IY26685 (AIX 4.3) or APAR IY25528 (AIX 5.1). It also requires a
fix for another AIX Assembler bug and a co-dependent AIX Archiver fix
referenced as APAR IY53606 (AIX 5.2) or as APAR IY54774 (AIX 5.1)

‘libstdc++’ in GCC 3.4 increments the major version number of the
shared object and GCC installation places the libstdc++.a
shared library in a common location which will overwrite the and GCC
3.3 version of the shared library. Applications either need to be
re-linked against the new shared library or the GCC 3.1 and GCC 3.3
versions of the ‘libstdc++’ shared object needs to be available
to the AIX runtime loader. The GCC 3.1 ‘libstdc++.so.4’, if
present, and GCC 3.3 ‘libstdc++.so.5’ shared objects can be
installed for runtime dynamic loading using the following steps to set
the ‘F_LOADONLY’ flag in the shared object for each
multilib libstdc++.a installed:

Extract the shared objects from the currently installed
libstdc++.a archive:

% ar -x libstdc++.a libstdc++.so.4 libstdc++.so.5

Enable the ‘F_LOADONLY’ flag so that the shared object will be
available for runtime dynamic loading, but not linking:

Linking executables and shared libraries may produce warnings of
duplicate symbols. The assembly files generated by GCC for AIX always
have included multiple symbol definitions for certain global variable
and function declarations in the original program. The warnings should
not prevent the linker from producing a correct library or runnable
executable.

AIX 4.3 utilizes a “large format” archive to support both 32-bit and
64-bit object modules. The routines provided in AIX 4.3.0 and AIX 4.3.1
to parse archive libraries did not handle the new format correctly.
These routines are used by GCC and result in error messages during
linking such as “not a COFF file”. The version of the routines shipped
with AIX 4.3.1 should work for a 32-bit environment. The -g
option of the archive command may be used to create archives of 32-bit
objects using the original “small format”. A correct version of the
routines is shipped with AIX 4.3.2 and above.

Some versions of the AIX binder (linker) can fail with a relocation
overflow severe error when the -bbigtoc option is used to link
GCC-produced object files into an executable that overflows the TOC. A fix
for APAR IX75823 (OVERFLOW DURING LINK WHEN USING GCC AND -BBIGTOC) is
available from IBM Customer Support and from its
techsupport.services.ibm.com
website as PTF U455193.

The AIX 4.3.2.1 linker (bos.rte.bind_cmds Level 4.3.2.1) will dump core
with a segmentation fault when invoked by any version of GCC. A fix for
APAR IX87327 is available from IBM Customer Support and from its
techsupport.services.ibm.com
website as PTF U461879. This fix is incorporated in AIX 4.3.3 and above.

The initial assembler shipped with AIX 4.3.0 generates incorrect object
files. A fix for APAR IX74254 (64BIT DISASSEMBLED OUTPUT FROM COMPILER FAILS
TO ASSEMBLE/BIND) is available from IBM Customer Support and from its
techsupport.services.ibm.com
website as PTF U453956. This fix is incorporated in AIX 4.3.1 and above.

AIX provides National Language Support (NLS). Compilers and assemblers
use NLS to support locale-specific representations of various data
formats including floating-point numbers (e.g., ‘.’ vs ‘,’ for
separating decimal fractions). There have been problems reported where
GCC does not produce the same floating-point formats that the assembler
expects. If one encounters this problem, set the LANG
environment variable to ‘C’ or ‘En_US’.

A default can be specified with the -mcpu=cpu_type
switch and using the configure option --with-cpu-cpu_type.

iq2000-*-elf

Vitesse IQ2000 processors. These are used in embedded
applications. There are no standard Unix configurations.

lm32-*-elf

Lattice Mico32 processor.
This configuration is intended for embedded systems.

lm32-*-uclinux

m32c-*-elf

Renesas M32C processor.
This configuration is intended for embedded systems.

m32r-*-elf

Renesas M32R processor.
This configuration is intended for embedded systems.

m68k-*-*

By default,
‘m68k-*-elf*’, ‘m68k-*-rtems’, ‘m68k-*-uclinux’ and
‘m68k-*-linux’
build libraries for both M680x0 and ColdFire processors. If you only
need the M680x0 libraries, you can omit the ColdFire ones by passing
--with-arch=m68k to configure. Alternatively, you
can omit the M680x0 libraries by passing --with-arch=cf to
configure. These targets default to 5206 or 5475 code as
appropriate for the target system when
configured with --with-arch=cf and 68020 code otherwise.

The ‘m68k-*-netbsd’ and
‘m68k-*-openbsd’ targets also support the --with-arch
option. They will generate ColdFire CFV4e code when configured with
--with-arch=cf and 68020 code otherwise.

You can override the default processors listed above by configuring
with --with-cpu=target. This target can either
be a -mcpu argument or one of the following values:
‘m68000’, ‘m68010’, ‘m68020’, ‘m68030’,
‘m68040’, ‘m68060’, ‘m68020-40’ and ‘m68020-60’.

GCC requires at least binutils version 2.17 on these targets.

m68k-*-uclinux

GCC 4.3 changed the uClinux configuration so that it uses the
‘m68k-linux-gnu’ ABI rather than the ‘m68k-elf’ ABI.
It also added improved support for C++ and flat shared libraries,
both of which were ABI changes.

mep-*-elf

microblaze-*-elf

Xilinx MicroBlaze processor.
This configuration is intended for embedded systems.

mips-*-*

If on a MIPS system you get an error message saying “does not have gp
sections for all it's [sic] sectons [sic]”, don't worry about it. This
happens whenever you use GAS with the MIPS linker, but there is not
really anything wrong, and it is okay to use the output file. You can
stop such warnings by installing the GNU linker.

It would be nice to extend GAS to produce the gp tables, but they are
optional, and there should not be a warning about their absence.

The libstdc++ atomic locking routines for MIPS targets requires MIPS II
and later. A patch went in just after the GCC 3.3 release to
make ‘mips*-*-*’ use the generic implementation instead. You can also
configure for ‘mipsel-elf’ as a workaround. The
‘mips*-*-linux*’ target continues to use the MIPS II routines. More
work on this is expected in future releases.

The built-in __sync_* functions are available on MIPS II and
later systems and others that support the ‘ll’, ‘sc’ and
‘sync’ instructions. This can be overridden by passing
--with-llsc or --without-llsc when configuring GCC.
Since the Linux kernel emulates these instructions if they are
missing, the default for ‘mips*-*-linux*’ targets is
--with-llsc. The --with-llsc and
--without-llsc configure options may be overridden at compile
time by passing the -mllsc or -mno-llsc options to
the compiler.

MIPS systems check for division by zero (unless
-mno-check-zero-division is passed to the compiler) by
generating either a conditional trap or a break instruction. Using
trap results in smaller code, but is only supported on MIPS II and
later. Also, some versions of the Linux kernel have a bug that
prevents trap from generating the proper signal (SIGFPE). To enable
the use of break, use the --with-divide=breaksconfigure option when configuring GCC. The default is to
use traps on systems that support them.

The assembler from GNU binutils 2.17 and earlier has a bug in the way
it sorts relocations for REL targets (o32, o64, EABI). This can cause
bad code to be generated for simple C++ programs. Also the linker
from GNU binutils versions prior to 2.17 has a bug which causes the
runtime linker stubs in very large programs, like libgcj.so, to
be incorrectly generated. GNU Binutils 2.18 and later (and snapshots
made after Nov. 9, 2006) should be free from both of these problems.

mips-sgi-irix5

Support for IRIX 5 has been removed in GCC 4.6.

mips-sgi-irix6

Support for IRIX 6.5 has been obsoleted in GCC 4.7, but can still be
enabled by configuring with --enable-obsolete. Support will be
removed in GCC 4.8. Support for IRIX 6 releases before 6.5 has been
removed in GCC 4.6, as well as support for the O32 ABI. It is
strongly recommended to upgrade to at least IRIX 6.5.18. This
release introduced full ISO C99 support, though for the N32 and N64 ABIs
only.

To build and use GCC on IRIX 6.5, you need the IRIX Development Foundation
(IDF) and IRIX Development Libraries (IDL). They are included with the
IRIX 6.5 media.

If you are using SGI's MIPSpro cc as your bootstrap compiler, you must
ensure that the N32 ABI is in use. To test this, compile a simple C
file with cc and then run file on the
resulting object file. The output should look like:

test.o: ELF N32 MSB ...

If you see:

test.o: ELF 32-bit MSB ...

or

test.o: ELF 64-bit MSB ...

then your version of cc uses the O32 or N64 ABI by default. You
should set the environment variable CC to ‘cc -n32’
before configuring GCC.

If you want the resulting gcc to run on old 32-bit systems
with the MIPS R4400 CPU, you need to ensure that only code for the ‘mips3’
instruction set architecture (ISA) is generated. While GCC 3.x does
this correctly, both GCC 2.95 and SGI's MIPSpro cc may change
the ISA depending on the machine where GCC is built. Using one of them
as the bootstrap compiler may result in ‘mips4’ code, which won't run at
all on ‘mips3’-only systems. For the test program above, you should see:

test.o: ELF N32 MSB mips-3 ...

If you get:

test.o: ELF N32 MSB mips-4 ...

instead, you should set the environment variable CC to ‘cc
-n32 -mips3’ or ‘gcc -mips3’ respectively before configuring GCC.

MIPSpro C 7.4 may cause bootstrap failures, due to a bug when inlining
memcmp. Either add -U__INLINE_INTRINSICS to the CC
environment variable as a workaround or upgrade to MIPSpro C 7.4.1m.

GCC on IRIX 6.5 is usually built to support the N32 and N64 ABIs. If
you build GCC on a system that doesn't have the N64 libraries installed
or cannot run 64-bit binaries,
you need to configure with --disable-multilib so GCC doesn't
try to use them.
Look for /usr/lib64/libc.so.1 to see if you
have the 64-bit libraries installed.

GCC must be configured with GNU as. The latest version, from GNU
binutils 2.22, is known to work. On the other hand, bootstrap fails
with GNU ld at least since GNU binutils 2.17.

The --enable-libgcj
option is disabled by default: IRIX 6 uses a very low default limit
(20480) for the command line length. Although libtool contains a
workaround for this problem, at least the N64 ‘libgcj’ is known not
to build despite this, running into an internal error of the native
ld. A sure fix is to increase this limit (‘ncargs’) to
its maximum of 262144 bytes. If you have root access, you can use the
systune command to do this.

wchar_t support in ‘libstdc++’ is not available for old
IRIX 6.5.x releases, x < 19. The problem cannot be autodetected
and in order to build GCC for such targets you need to configure with
--disable-wchar_t.

s390-*-linux*

s390x-*-linux*

zSeries system (64-bit) running GNU/Linux for zSeries.

s390x-ibm-tpf*

zSeries system (64-bit) running TPF. This platform is
supported as cross-compilation target only.

*-*-solaris2*

Support for Solaris 8 has been obsoleted in GCC 4.7, but can still be
enabled by configuring with --enable-obsolete. Support will be
removed in GCC 4.8. Support for Solaris 7 has been removed in GCC 4.6.

Sun does not ship a C compiler with Solaris 2 before Solaris 10, though
you can download the Sun Studio compilers for free. In Solaris 10 and
11, GCC 3.4.3 is available as /usr/sfw/bin/gcc. Solaris 11
also provides GCC 4.5.2 as /usr/gcc/4.5/bin/gcc. Alternatively,
you can install a pre-built GCC to bootstrap and install GCC. See the
binaries page for details.

The Solaris 2 /bin/sh will often fail to configure
‘libstdc++-v3’, ‘boehm-gc’ or ‘libjava’. We therefore
recommend using the following initial sequence of commands

% CONFIG_SHELL=/bin/ksh
% export CONFIG_SHELL

and proceed as described in the configure instructions.
In addition we strongly recommend specifying an absolute path to invoke
srcdir/configure.

Solaris 2 comes with a number of optional OS packages. Some of these
are needed to use GCC fully, namely SUNWarc,
SUNWbtool, SUNWesu, SUNWhea, SUNWlibm,
SUNWsprot, and SUNWtoo. If you did not install all
optional packages when installing Solaris 2, you will need to verify that
the packages that GCC needs are installed.

To check whether an optional package is installed, use
the pkginfo command. To add an optional package, use the
pkgadd command. For further details, see the Solaris 2
documentation.

Trying to use the linker and other tools in
/usr/ucb to install GCC has been observed to cause trouble.
For example, the linker may hang indefinitely. The fix is to remove
/usr/ucb from your PATH.

The build process works more smoothly with the legacy Sun tools so, if you
have /usr/xpg4/bin in your PATH, we recommend that you place
/usr/bin before /usr/xpg4/bin for the duration of the build.

We recommend the use of the Sun assembler or the GNU assembler, in
conjunction with the Sun linker. The GNU as
versions included in Solaris 10, from GNU binutils 2.15, and Solaris 11,
from GNU binutils 2.19, are known to work. They can be found in
/usr/sfw/bin/gas. Current versions of GNU binutils (2.22)
are known to work as well. Note that your mileage may vary
if you use a combination of the GNU tools and the Sun tools: while the
combination GNU as + Sun ld should reasonably work,
the reverse combination Sun as + GNU ld may fail to
build or cause memory corruption at runtime in some cases for C++ programs.
GNU ld usually works as well, although the version included in
Solaris 10 cannot be used due to several bugs. Again, the current
version (2.22) is known to work, but generally lacks platform specific
features, so better stay with Sun ld. To use the LTO linker
plugin (-fuse-linker-plugin) with GNU ld, GNU
binutils must be configured with --enable-largefile.

To enable symbol versioning in ‘libstdc++’ with Sun ld,
you need to have any version of GNU c++filt, which is part of
GNU binutils. ‘libstdc++’ symbol versioning will be disabled if no
appropriate version is found. Sun c++filt from the Sun Studio
compilers does not work.

Sun bug 4296832 turns up when compiling X11 headers with GCC 2.95 or
newer: g++ will complain that types are missing. These headers
assume that omitting the type means int; this assumption worked for
C90 but is wrong for C++, and is now wrong for C99 also.

g++ accepts such (invalid) constructs with the option
-fpermissive; it will assume that any missing type is int
(as defined by C90).

There are patches for Solaris 8 (108652-24 or newer for SPARC,
108653-22 for Intel) that fix this bug.

Sun bug 4927647 sometimes causes random spurious testsuite failures
related to missing diagnostic output. This bug doesn't affect GCC
itself, rather it is a kernel bug triggered by the expect
program which is used only by the GCC testsuite driver. When the bug
causes the expect program to miss anticipated output, extra
testsuite failures appear.

There are patches for Solaris 8 (117350-12 or newer for SPARC,
117351-12 or newer for Intel) and Solaris 9 (117171-11 or newer for
SPARC, 117172-11 or newer for Intel) that address this problem.

Solaris 8 provides an alternate implementation of the thread
library ‘libthread’. It is required for TLS support and has
been made the default in Solaris 9, so it is always used on
Solaris 8.

Thread-local storage (TLS) is supported in Solaris 8 and 9, but requires
some patches. The ‘libthread’ patches provide the
__tls_get_addr (SPARC, 64-bit x86) resp. ___tls_get_addr
(32-bit x86) functions. On Solaris 8, you need 108993-26 or newer on
SPARC, 108994-26 or newer on Intel. On Solaris 9, the necessary support
on SPARC is present since FCS, while 114432-05 or newer is required on
Intel. Additionally, on Solaris 8, patch 109147-14 or newer on SPARC or
109148-22 or newer on Intel are required for the Sun ld and
runtime linker (ld.so.1) support. Again, Solaris 9/SPARC
works since FCS, while 113986-02 is required on Intel. The linker
patches must be installed even if GNU ld is used. Sun
as in Solaris 8 and 9 doesn't support the necessary
relocations, so GNU as must be used. The configure
script checks for those prerequisites and automatically enables TLS
support if they are met. Although those minimal patch versions should
work, it is recommended to use the latest patch versions which include
additional bug fixes.

sparc*-*-*

This section contains general configuration information for all
SPARC-based platforms. In addition to reading this section, please
read all other sections that match your target.

Newer versions of the GNU Multiple Precision Library (GMP), the MPFR
library and the MPC library are known to be miscompiled by earlier
versions of GCC on these platforms. We therefore recommend the use
of the exact versions of these libraries listed as minimal versions
in the prerequisites.

sparc-sun-solaris2*

When GCC is configured to use GNU binutils 2.14 or later, the binaries
produced are smaller than the ones produced using Sun's native tools;
this difference is quite significant for binaries containing debugging
information.

Starting with Solaris 7, the operating system is capable of executing
64-bit SPARC V9 binaries. GCC 3.1 and later properly supports
this; the -m64 option enables 64-bit code generation.
However, if all you want is code tuned for the UltraSPARC CPU, you
should try the -mtune=ultrasparc option instead, which produces
code that, unlike full 64-bit code, can still run on non-UltraSPARC
machines.

When configuring on a Solaris 7 or later system that is running a kernel
that supports only 32-bit binaries, one must configure with
--disable-multilib, since we will not be able to build the
64-bit target libraries.

GCC 3.3 and GCC 3.4 trigger code generation bugs in earlier versions of
the GNU compiler (especially GCC 3.0.x versions), which lead to the
miscompilation of the stage1 compiler and the subsequent failure of the
bootstrap process. A workaround is to use GCC 3.2.3 as an intermediary
stage, i.e. to bootstrap that compiler with the base compiler and then
use it to bootstrap the final compiler.

GCC 3.4 triggers a code generation bug in versions 5.4 (Sun ONE Studio 7)
and 5.5 (Sun ONE Studio 8) of the Sun compiler, which causes a bootstrap
failure in form of a miscompilation of the stage1 compiler by the Sun
compiler. This is Sun bug 4974440. This is fixed with patch 112760-07.

GCC 3.4 changed the default debugging format from Stabs to DWARF-2 for
32-bit code on Solaris 7 and later. If you use the Sun assembler, this
change apparently runs afoul of Sun bug 4910101 (which is referenced as
an x86-only problem by Sun, probably because they do not use DWARF-2).
A symptom of the problem is that you cannot compile C++ programs like
groff 1.19.1 without getting messages similar to the following:

To work around this problem, compile with -gstabs+ instead of
plain -g.

When configuring the GNU Multiple Precision Library (GMP), the MPFR
library or the MPC library on a Solaris 7 or later system, the canonical
target triplet must be specified as the build parameter on the
configure line. This target triplet can be obtained by invoking ./config.guess in the toplevel source directory of GCC (and
not that of GMP or MPFR or MPC). For example on a Solaris 9 system:

% ./configure --build=sparc-sun-solaris2.9 --prefix=xxx

sparc-sun-solaris2.10

There is a bug in older versions of the Sun assembler which breaks
thread-local storage (TLS). A typical error message is

sparc-*-linux*

sparc64-*-solaris2*

When configuring the GNU Multiple Precision Library (GMP), the MPFR
library or the MPC library, the canonical target triplet must be specified
as the build parameter on the configure line. For example
on a Solaris 9 system:

% ./configure --build=sparc64-sun-solaris2.9 --prefix=xxx

The following compiler flags must be specified in the configure
step in order to bootstrap this target with the Sun compiler:

% CC="cc -xarch=v9 -xildoff" srcdir/configure [options] [target]

-xarch=v9 specifies the SPARC-V9 architecture to the Sun toolchain
and -xildoff turns off the incremental linker.

sparcv9-*-solaris2*

This is a synonym for ‘sparc64-*-solaris2*’.

c6x-*-*

The C6X family of processors. This port requires binutils-2.22 or newer.

tilegx-*-linux*

tilepro-*-linux*

*-*-vxworks*

Support for VxWorks is in flux. At present GCC supports only the
very recent VxWorks 5.5 (aka Tornado 2.2) release, and only on PowerPC.
We welcome patches for other architectures supported by VxWorks 5.5.
Support for VxWorks AE would also be welcome; we believe this is merely
a matter of writing an appropriate “configlette” (see below). We are
not interested in supporting older, a.out or COFF-based, versions of
VxWorks in GCC 3.

VxWorks comes with an older version of GCC installed in
$WIND_BASE/host; we recommend you do not overwrite it.
Choose an installation prefix entirely outside $WIND_BASE.
Before running configure, create the directories prefix
and prefix/bin. Link or copy the appropriate assembler,
linker, etc. into prefix/bin, and set your PATH to
include that directory while running both configure and
make.

You must give configure the
--with-headers=$WIND_BASE/target/h switch so that it can
find the VxWorks system headers. Since VxWorks is a cross compilation
target only, you must also specify --target=target.
configure will attempt to create the directory
prefix/target/sys-include and copy files into it;
make sure the user running configure has sufficient privilege
to do so.

GCC's exception handling runtime requires a special “configlette”
module, contrib/gthr_supp_vxw_5x.c. Follow the instructions in
that file to add the module to your kernel build. (Future versions of
VxWorks will incorporate this module.)

x86_64-*-*, amd64-*-*

GCC supports the x86-64 architecture implemented by the AMD64 processor
(amd64-*-* is an alias for x86_64-*-*) on GNU/Linux, FreeBSD and NetBSD.
On GNU/Linux the default is a bi-arch compiler which is able to generate
both 64-bit x86-64 and 32-bit x86 code (via the -m32 switch).

x86_64-*-solaris2.1[0-9]*

GCC also supports the x86-64 architecture implemented by the AMD64
processor (‘amd64-*-*’ is an alias for ‘x86_64-*-*’) on
Solaris 10 or later. Unlike other systems, without special options a
bi-arch compiler is built which generates 32-bit code by default, but
can generate 64-bit x86-64 code with the -m64 switch. Since
GCC 4.7, there is also configuration that defaults to 64-bit code, but
can generate 32-bit code with -m32. To configure and build
this way, you have to provide all support libraries like libgmp
as 64-bit code, configure with --target=x86_64-pc-solaris2.1x
and ‘CC=gcc -m64’.

xtensa*-*-elf

This target is intended for embedded Xtensa systems using the
‘newlib’ C library. It uses ELF but does not support shared
objects. Designed-defined instructions specified via the
Tensilica Instruction Extension (TIE) language are only supported
through inline assembly.

The Xtensa configuration information must be specified prior to
building GCC. The include/xtensa-config.h header
file contains the configuration information. If you created your
own Xtensa configuration with the Xtensa Processor Generator, the
downloaded files include a customized copy of this header file,
which you can use to replace the default header file.

xtensa*-*-linux*

This target is for Xtensa systems running GNU/Linux. It supports ELF
shared objects and the GNU C library (glibc). It also generates
position-independent code (PIC) regardless of whether the
-fpic or -fPIC options are used. In other
respects, this target is the same as the
‘xtensa*-*-elf’ target.

Microsoft Windows

Intel 16-bit versions

The 16-bit versions of Microsoft Windows, such as Windows 3.1, are not
supported.

However, the 32-bit port has limited support for Microsoft
Windows 3.11 in the Win32s environment, as a target only. See below.

Intel 32-bit versions

The 32-bit versions of Windows, including Windows 95, Windows NT, Windows
XP, and Windows Vista, are supported by several different target
platforms. These targets differ in which Windows subsystem they target
and which C libraries are used.

*-*-cygwin

GCC will build under Cygwin without modification; it does not build
with Microsoft's C++ compiler and there are no plans to make it do so.

The Cygwin native compiler can be configured to target any 32-bit x86
cpu architecture desired; the default is i686-pc-cygwin. It should be
used with as up-to-date a version of binutils as possible; use either
the latest official GNU binutils release in the Cygwin distribution,
or version 2.20 or above if building your own.

*-*-interix

The Interix target is used by OpenNT, Interix, Services For UNIX (SFU),
and Subsystem for UNIX-based Applications (SUA). Applications compiled
with this target run in the Interix subsystem, which is separate from
the Win32 subsystem. This target was last known to work in GCC 3.3.

*-*-mingw32

GCC will build with and support only MinGW runtime 3.12 and later.
Earlier versions of headers are incompatible with the new default semantics
of extern inline in -std=c99 and -std=gnu99 modes.

Older systems

GCC contains support files for many older (1980s and early
1990s) Unix variants. For the most part, support for these systems
has not been deliberately removed, but it has not been maintained for
several years and may suffer from bitrot.

Starting with GCC 3.1, each release has a list of “obsoleted” systems.
Support for these systems is still present in that release, but
configure will fail unless the --enable-obsolete
option is given. Unless a maintainer steps forward, support for these
systems will be removed from the next release of GCC.

Support for old systems as hosts for GCC can cause problems if the
workarounds for compiler, library and operating system bugs affect the
cleanliness or maintainability of the rest of GCC. In some cases, to
bring GCC up on such a system, if still possible with current GCC, may
require first installing an old version of GCC which did work on that
system, and using it to compile a more recent GCC, to avoid bugs in the
vendor compiler. Old releases of GCC 1 and GCC 2 are available in the
old-releases directory on the GCC mirror sites. Header bugs may generally be avoided using
fixincludes, but bugs or deficiencies in libraries and the
operating system may still cause problems.

Support for older systems as targets for cross-compilation is less
problematic than support for them as hosts for GCC; if an enthusiast
wishes to make such a target work again (including resurrecting any of
the targets that never worked with GCC 2, starting from the last
version before they were removed), patches
following the usual requirements would be
likely to be accepted, since they should not affect the support for more
modern targets.

For some systems, old versions of GNU binutils may also be useful,
and are available from pub/binutils/old-releases on
sourceware.org mirror sites.

Some of the information on specific systems above relates to
such older systems, but much of the information
about GCC on such systems (which may no longer be applicable to
current GCC) is to be found in the GCC texinfo manual.

all ELF targets (SVR4, Solaris 2, etc.)

C++ support is significantly better on ELF targets if you use the
GNU linker; duplicate copies of
inlines, vtables and template instantiations will be discarded
automatically.